This bug will be addressed 1) webview and iframe which is, alao, the standard
way to embed something like a YouTube video.

Try http://jgromit.com/gromit/videos/slides/jalbumvideo_560by315.html.
Remember, YouTube is now defaulting to their HTML5 player, not Flash.

It's not a generalized problem with iframes - it seems to be a problem only
in that YouTube (and Vimeo) is having trouble recognizing the browser.
Simpler iframes work fine - see http://jgromit.jalbum.net/MatrixIframe/

Test with Win10 and OSX 10.10.5 platforms. But the YouTube & Vimeo iframe
problem shows up clearly on both platforms, so it's not something
OS-specific.

Open that link in WebView on any platform, and you should see the failure.
Open it in any browser, and it should work fine. The YouTube embedding on
that page is absolutely plain-vanilla, per YouTube specs (the div's that wrap
around the iframe are just for styling - position, size, etc.). The next
slide page from there is a Vimeo embed - same problem, different player.

It might have something to do with mixed content (the embeds use https, while
the containing page does not), but a quick test showed no difference in
behavior. I think the YouTube and Vimeo players simply don't know that
WebView can handle HTML5 video, so they choke.